Electric resistor



Feb. 15, 1955 R. E. DU BOIS 2,702,332

ELECTRIC RESISTOR Filed Feb. 27, 1952 INVENTOR ROBERT E. Du BOIS ATTORNEY United States Patent ELECTRIC RESISTOR Robert E. Du Bois, Hammond, .Ind.

Application February 27, 1952, Serial No. 273,688

8 Claims. (Cl. 201-74) This invention relates to resistors for dissipating electrical energy such as that generated by dynamic braking systems on locomotives.

It is the primary object of this invention to provide a resistor structure in which the amount of resistor material, and the space it must occupy, is reduced to a minimum for dissipating a given amount of electrical energy.

A specific object of this invention is to provide an improved heat dissipating resistor structure of the forced ventilation type.

Another object of the invention is to provide an improved heat dissipating resistor of such a design that expansion and contraction of the resistor is freely permitted without detrimental effects to the resistor material.

A further object of this invention is to provide an improved heat dissipating resistor of the forced ventilation type, where a single edge-wound resistor ribbon is placed about a centrifugal blower in such manner as to increase the efiiciency with which air from the blower will aid in removing the heat from the resistor.

Another object of this invention is to provide a spiral resistor angularly wound on one edge as a heat dissipator of the forced ventilation type.

With the foregoing and other objects in view, the invention resides in the following specification and appended claims, certain embodiments and details of construction of which are shown in the accompanying drawings in which:

Figure 1 is a partially sectioned view in side elevation of the invention;

Figure 2 is a plan view of the invention taken along the lines 2-2 of Figure 1;

Figure 3 is a partially sectioned view in side elevation of a modified form of the invention;

Figure 4 is a plan view of the invention taken along the lines 4-4 of Figure 3.

Referring more particularly to Figure 1, a resistor 1 consisting of a single piece of fiat sheet resistor material edgewound in spiral form is carried by a plurality of clips 2 extending inwardly from a plurality of mounting posts shown generally at 3. The convolutions of resistor 1 are inclined with respect to the common central axis of the spirally wound resistor. Each post 3 comprises a bolt 4 threaded into a base 5 at 6. Carried by bolts 4 are insulating spacers 7. Clips 2 of insulating material are firmly held about rods 4 between adjacent spacers 7. The spacers 7 are designed to position the inner ends 8 of each clip to receive in free supporting relationship a portion of a convolution of the spiral resistor 1. Each end of the resistor 1 is secured to a post 3, the top connection being shown at 9 in Fig. 1. The method of connection is not important to the invention, nor are the terminal connections (not shown), which would be made at such end connections.

Mounted within the convolutions of resistor 1 is a centrifugal blower 10 of any suitable design, herein being shown as having an impeller 11 with integral blades 12 about its periphery. The impeller 11 is driven through a drive shaft 13 by an electric motor (not shown). A dust cover 14, having a flange 15 extending under the heads 16 of bolts 4, is provided for the whole structure.

The operation of the invention should appear obvious to one skilled in the art. When it is desired to 2,702,332 Patented Feb- 15, 1955 dissipate electrical energy from any source, connection is made to the resistor 1 and the driving motor for the blower 10 is energized. The air from the impeller blades 12 will impinge against the upwardly inclined convolutions of resistor 1, and thereby carry away the heat generated by said resistor. Due to the inclination of the resistor, the air impinging on its upper surface will effect a scouring action to take away the heat generated much faster than were the resistor surface not inclined. Air passing through the convolutions of a resistor 1 will also contact and act to speed up the heat removed from the bottom surface of the resistor. This is due primarily to the fact that air striking the inclined surface of one convolution is directed upwardly and will contact the lower surface of the convolution directly above it. Since this construction will permit a more rapid dissipation of heat, it is possible to make the resistor 1 shorter in length, thereby using less material, being more economical and conserving space.

When the resistor 1 heats up, its inherent tendency to expand is permitted between the end connections of the resistor by the free supporting relationship between the convolutions of the resistor and the clips 2. The clips 2 also prevent any contact between adjacent convolutions of the resistor 1.

The modification shown in Figs. 3 and 4 is identical in all respects except for the mounting means for the resistor 1. This structure omits the use of the supporting clips and shows resistor 1 perforated at 17 to receive the bolts 4. Spacers 18 are provided to separate the plurality of convolutions of the resistor. This construction is feasible but not as efi'icient as the preferred embodiment of Figures 1 and 2 because the mounting means does not provide for free expansion between the end connections of the resistor. The operation, of course, is the same as previously discussed.

It is realized that many modifications of the invention may be designed primarily with respect to the mounting means. However, the important advance in the resistor art, achieved by the invention, is the provision of an inclined edge-wound resistor in connection with a source of forced draft to reduce the amount of material necessary in the resistor and the cost of the material.

I claim:

1. A resistor comprising a single piece of flat sheet resistor material edgewound in spiral form producing thereby a series of convolutions, said convolutions being inclined with respect to the central axis of the spiral form of the resistor throughout the length of said resistor.

2. A resistor comprising a single piece of flat sheet resistor material edgewound into a plurality of convolutions with a common central axis, said convolutions being inclined with respect to said axis throughout the length of the resistor.

3. A resistor structure comprising a single piece of flat sheet resistor material edgewound into a plurality of convolutions with a common central axis, said convolutions being inclined with respect to said axis throughout the length of the resistor, mounting means for the resistor, means to connect each end of the resistor to the mounting means, and means to freely support and space the convolutions of said resistor between said end connecting means.

4. A resistor structure comprising a single piece of flat sheet resistor material edgewound in spiral form producing thereby a series of convolutions, said convolutions being inclined with respect to the central axis of the spiral form of the resistor throughout the length of the resistor, mounting means for the resistor, means to connect each end of the resistor to the mounting means, and means to freely support and space the convolutions of said resistor between said connection means.

5. A forced draft resistor structure comprising a single piece of resistor material edgewound in spiral form producing thereby a series of convolutions, said convolutions being inclined with respect to the central axis of the spiral form of the resistor throughout the length of the resistor, and means for directing a cooling medium outwardly from within the space defined by the resistor convolutions to cool said resistor.

6. A forced draft resistor structure comprising a single piece of resistor material edgewound in spiral form producing thereby a series of convolutions, said convolutions being inclined with respect to the central axis of the spiral form throughout the length of the resistor, mounting means for the resistor, means to connect each end of the resistor to the mounting means, and means to direct air outwardly from within the space defined by the resistor convolutions to cool said resistor.

7. A forced draft resistor structure comprising a single piece of resistor material edgewound in spiral form producing thereby a series of convolutions, said convolutions being inclined with respect to the central axis of the spiral form throughout the length of the resistor, mounting means for the resistor, means to connect each end of the resistor to the mounting means, means to freely support and space the convolutions of said resistor between said connection means, and centrifugal blower means carried within the space defined by the convolutions for directing air outwardly against and past said convolutions.

8. A forced draft resistor structure comprising a single piece of resistor material edgewound in spiral form producing thereby a series of convolutions, said convolutions being inclined with respect to the central axis of the spiral form throughout the length of the resistor, mounting means for the resistor, means to connect each end of the resistor to the mounting means, means to connect each convolution of the resistor to the mounting means at a plurality of points, and centrifugal blower means carried within the space defined by the convolutions for directing air outwardly against and past said convolutions.

References Cited in the file of this patent UNITED STATES PATENTS i y u. v 

